Piston ring



July 12, 1927. 3 40 'R. GRO VER PISTON RING Filed July 27. 1925INVENTOR.

f/w i A TTORNEYS.

lap complementary surfaces formed in the opposite end of the ring tosubstantially the extent of the entire length of the tongue.

The effectiveness of a seal produced by a piston ring'is in a generalway proportionate to the degree of overlap in the stepped sealed jointbetween its free ends. It is, therefore, 'of great importance that thetongues 6 and 7 should have rectilinear margins whereby to fit closelyto surfaces 4:, 5 and 9 substantially throughout the length of eachtongue. An equivalent degree of overlap cannot otherwise be obtainedwith a given degree of ring contraction following the making of the cutat 3. Since the degree of permissible contraction is limited by theamount of'expanding pressure which it is permissible forthe ring toexert upon the wall of a confining cylinder, it will be ob vidus that itis desirable to extend the effective degree of overlap between the endsof the piston as far as possible for a given degree of contraction. i

It will be noted, furthermore, that the rectilinear tongues whereby theoverlap between the ends of my improved ring is made effective, arelocated in the outer periphery of the ring where they may operate topresent a substantial continuous peripheral packing to resist thepassage of gases along a piston with which this ring is associated. Ifthe tongues were on the inside and the shoulders 12 and 13 were in theouter periphery of the ring, the ring would ob" viously not be gas tightand there would be no object for providing rectilinear margins on thetongues 6 and 7.

It has been found inactual practice that after-actual and protracted useof rings embodying this invention in the cylinders of internalcombustion engines, there is n-o carbon deposit between tongues G and 7or between such tongues and the web surfaces 4-,

V and 5, but that such surfaces are bright'and sary' but is pref-erredfor the reason that the web portions have inherently greater strengththan a corresponding thickness of tongue and, furthermore, the outerperiphseen that by providing a split ring, having a stepped sealed jointand with rectilinear staggered tongues in its outer periphery, I havesatisfied the objects of the inventionas above specified and havedisclosed a ring'in which the entire length of each of the tongues atits ends is availablefor sealing purposes and is operatively" in gastight, contact throughout its length with complementary surfaces on theopposite end of the ring. Even though such a ring becomes worn andexpands during use until merely the extreme ends of tongues 6 and 7overlap surfaces t and 5, the seal will be preserved due to the factthat the tongues have rectilinear margins to their extreme ends.

I claim: 1 i

A piston ring comprising'a split ring havin g square cut transverseshoulders adjacent its ends on its inner periphery and provided in itsouter periphery with marginal recesses substantially square cut in crosssection and disposed on opposite sides of their respective ends withsubstantially plane radially router bearing surfaces continuous to saidshoulders, and tongues projecting beyond the shoulders at the end of thering and formed with laterally inner bearing surfaces complementary toeach other and radially inner surfaces complementary to the radiallyouter surfaces of said recesses, the ends of said tongues beingsubstantially square cut and their radially inner bearing surfaces beingcontinuous substantially to their respectiveends, whereby said tonguesare adapted to maintain an effective seal in any position of overlap.

' RAY GROVER

